Contemporary computer and telecommunication equipment is usually realized through the use of printed circuit card assemblies. The printed circuit boards comprise a flat substrate material having one or more layers of circuit conductors on one or both sides thereof. In view of the complexity of some circuits and components, a printed circuit board may be a very complex and hence a very expensive device to realize a circuit. In the design process of a system, it is quite often necessary to alter the circuit and hence the original pattern of conductors printed on the substrate. Since the redesign of a printed circuit board is a very expensive exercise, the problem of last-minute engineering changes is usually solved by applying overlay conductors over the original printed circuit.
In other instances, especially when a system performance is enhanced or modified for any reason, it is very often necessary to modify the printed pattern of conductors of some printed circuit card assemblies. This is again achieved through the use of overlay conductors or barnacles as they are often referred to in the art.
To this day, change interconnections are usually achieved through the use of wires connecting a pair of points on the board. This procedure is time consuming, labour intensive, tedious for the operator as well as being error prone in spite of some sophisticated mechanized aids. In addition to its considerable cost, the procedure usually results in an unsightly product prone to snagging of the wires and other problems such as cold solder joints.